John lee stevens



UNITED STATES PATENT OFFICE.

JOHN LEE STEVENS, OF KENNINGTON, ENGLAND.

FURNACE.

Specification of Letters Patent No. 11,975, dated November 21, 1854.

T all whom it may concern Be it known that I, JOHN LEE STEVENS, of Kennington, in the county of Surrey, England, have invented, made, and applied to use certain new and useful Improvements in Furnaces, for which Letters Patent were granted to me by Her Majesty the Queen of Great Britain on the first day of October, 1852, and for which I now desire to ob tain Letters Patent for the United States of America; and I do hereby declare that the following specification, taken in connection with the accompanying drawings, constitutes a full and exact description of the same.

This invention relates to double furnaces where the product from the fuel on one set of fire bars passes over or through the bright fire on the other set of fire bars which has heretofore been proposed to be accomlished in various ways and the improvements consist of applying the second fire bars above the first in such manner that the bridge at the back end is common to the two sets of bars and the fuel may be fed onto the two sets of bars through the one fire door.

The object of this invention is the more ,complete combustion of the products of the fuel as well as to prevent orlessen the formation of smoke which has heretofore been proposed to be accomplished in various ways, and in order that my invention may be most fully understood I will proceed to describe the same with reference to the accompanying drawings.

Figure 1 is a longitudinal and Fig. 2 a

transverse section of a furnace arranged or combined according to my invention applied to a steam boiler.

A, air passage; B, door way to second or upper furnace and from which second furnace ignited fuel descends on .to the first set of fire bars; C, first set of fire bars nearest the fioor; D, second or upper set of fire bars of one, two or more ranges according to the length of the furnace; E, aperture by which fuel passes over the second set of fire bars; F, plate between which and the bridge the products of the fuel on the first set of fire bars pass up and mix with the products from and over the other set of fire bars.

In large furnaces or those used for marine or other purposes wherein the fire is kept up continuously for many hours I protect the front of the plate with fire bricks carried by a bar about four inches above the ends of the fire bars D. G, course of the current of air; H, bridge serving for both sets of fire bars; a, 6, line of transverse section.

It will be seen by this description that while the first set of fire bars C is supplied with fuel over and through the second set of fire bars D the current of air G accumulating heat and velocity in a rapidly increasing ratio in consequence of its passing between two strata of fire as well as between the plate F and the bridge H which are naturally heated by the action of both fires, carries up wit-h it the products of the fire at C and mixes the products of the fire from D therewith, whereby the most attainable combustion is efiected and the formation of smoke materially lessened if not entirely prevented.

I am aware that previous arrangements have been made of sets of fire bars placed over each other and that various other means have been proposed for increasing the combustion of fuel and for consuming or lessening the formation of smoke. I do not therefore claim such arrangements or means otherwise than herein mentioned.

IVhat I claim is 1. Supplying the lower fire bars C, with and fifty-three.

" J. LEE STEVENS. Witnesses:

LEE W. SrEvENs, THOS. T. BELL. 

